1. Field of the Invention
The present invention relates to a network system, a proxy server, a session management method, and a program for communications using an active proxy.
2. Description of the Related Art
Conventionally, in case of communications using an active proxy, it is needed to maintain sessions by, for example, adding session information to a destination address. However, in this method, since a server is required to add the session information to a destination address, there is a risk that the session information may be easily leaked to other servers and a session may be stolen. Further, there is a problem that such a method cannot be applied to a case where communication is performed by using a different server within a series of sessions.
Further, among the Liberty Alliance specifications, a specification called LECP profile has the similar problem and it is difficult to realize such a specification, especially, in a session management method using cookies.
As examples of the related art of a proxy server, there are “system including proxy server and web server and program therefor” in which, when a web server in a coverage area does not return response information, a web client is informed the reason why the web server is stopped and estimated time for restarting, instead of a conventional error return (see, for example, Japanese Patent Application Laid-Open No. 2002-259338) and “proxy server and proxy control system” which suppress effects on other traffics in a network when obtaining content from an origin server (see, for example, Japanese Patent Application Laid-Open No. 2003-256321).